Since my truck does not have working A/C, and my commute is 40+ minutes one way, I have been toying with ideas on building a cheap portable A/C. I was originally looking at converting a cooler with some PC fans and copper, but this looks much easier solution to do.
http://www.instructables.com/id/Build-a-Discreet-USB-Air-Conditioner-with-a-Brita-/